Determination of postmortem interval (PMI) using histological changes in the cattle skin – A preliminary investigation

The estimation of the Postmortem interval (PMI) holds significant importance in forensic medicine, prompting continuous efforts to establish standardized methods for accuracy. Surprisingly, in the field of veterinary science, there remains a noticeable dearth of research dedicated to estimating the Postmortem interval. Addressing this research gap would undoubtedly enhance our understanding and expertise in veterinary forensics. Currently, there is no existing research on estimating the postmortem interval using histological changes in animal skin. This study involved collecting skin samples from the metatarsal region of 25 cattle carcasses at various postmortem intervals (0, 4, 8, 12, 24, 48, and 72 h) in Puducherry, India. The skin samples were processed using routine histological techniques and special staining methods, such as modified Alcian-Periodic Acid Schiff's (Alcian-PAS) staining and Masson Trichrome (MST), to further analyze the histological changes. Histological changes in the skin showed a normal appearance of the epidermis up to 4 h after death, followed by vacuolations and extensive degeneration leading to complete disintegration. In the dermis, rarefaction and collagenolysis were observed at 8 h post-death, progressing to complete fragmentation at 24 h post-death. The sebaceous glands remained normal until 24 h post-death, then showed autolytic changes resulting in complete disintegration at 48 h post-death. The sweat gland remained normal until 24 h post-death, after which degenerative changes were evident. After death, the hair follicles looked normal up to 8 h, but after that, changes like vacuoles and degeneration were observed. The study scored the skin based on these changes, finding that the dermis showed the strongest correlation with the postmortem interval (PMI), followed by the hair follicle and epidermis. Overall, histological variations in the skin are a reliable indicator for estimating the PMI in cattle carcasses.